Sometimes everything comes together perfectly in a photo and there is no need to remove anything. In my experience this is a rare case. It is always better to move the object in person rather than in Photoshop if at all possible.
This image provides a great example for when it is really not possible to remove the distraction in person. The power lines in this image are the perfect thing to leave up to Photoshop. It is much easier to remove them in post than it would be in person.
There are a few great ways to removing things from the background of your images.